The Farmer and the Viper aka: Farmer And The Viper
One winter a Farmer found a Viper frozen and numb with cold, and out of pity picked it up and placed it in his bosom. The Viper was no sooner revived by the warmth than it turned upon its benefactor and inflicted a fatal bite upon him; and as the poor man lay dying, he cried, "I have only got what I deserved, for taking compassion on so villainous a creature."
Johan Liebert from Monster kills his foster parents — many pairs thereof. Anyone who ever does anything remotely decent or nice for him ends up as the farmer to Johan's viper, but Tenma, the one who saved his life in the first place, gets the very worst of it through the horrible things that Johan does to others in order to "repay" him.
In a later episode of ARIA the NATURAL, Akari spots a woman who is dressed like she's just gotten back from a funeral. She is then told a ghost story about a woman in black who asks for transport, then spirits her gondolier away. That night, the woman in black asks Akari for a ride to a graveyard. Akari takes her (This is notably not the only example of Too Dumb to Live, because the anime consistently encourages naivety). Akari goes on her way, but the woman, in a weird subversion, grabs her hand and tries to spirit her away, specifically because she was impressed with Akari's kindness. The anime implies this to be a bad thing, but never makes it really clear. Cait Sith saves her, though, so we never find out.
In Dragon Ball Z, the last 5 minutes of Goku Vs. Frieza. After Frieza cuts himself in half with his own attack, Goku donates a small portion of his energy to him. As Frieza can survive in space, he ought to be able to get off the exploding planet with the energy. Due to Frieza being too arrogant to live, he uses it to attack Goku instead. Having used up his already unreasonably merciful last chance, Goku blows him to bits. He gets better but dies after THAT as well.
In Kino's Journey, Kino saves some stranded traders. It then turns out they trade human slaves and are looking to recuperate their losses.
In Vinland Saga, an English farmer and her daughter take pity on a young boy who stumble into their cottage, feeding and delousing him and sheltering him from the soldiers who are looking for a Viking spy and are killing all strangers on sight. In return, the boy burns down the village's dock, signaling the Vikings nearby to come take the village, which they do. Said boy is the protagonist.
In the first Fullmetal Alchemist anime, the disgraced and homeless Yoki is taken in by a group of Ishbalan refugees. He promptly betrays them by selling out the Serial Killer and fellow Ishbalan Scar to a bunch of bounty-hunters with the intent to split the bounty. The refugees don't take the idea of Yoki ratting out one of their own well and promptly give him a beat-down. Averted in Brotherhood and the manga.
Also Scar himself, after he kills Winry's parents after they give him lifesaving medical treatment. ...depending on the source material. In the first anime, it was Mustang being forced to do his job.
In the later chapters, the chimera Zampano, one of Edward's allies that Ed previously spared in battle, sneaks off and contacts the Military high command to rat them out. It's all a Batman Gambit though, planned to draw one of the homonculi to them so they can spring an ambush.
Done during the third season of Hell Girl. A teachers saves a quiet and shy acting girl student from being bullied. Afterwards, the girl's grandmother spends the episode trying to get the teacher fired, out of what appears to be jealously. Turns out the little girl was lying to her grandmother and claiming that it was the teacher who was bullying her. When the teacher confronts the girl after finding this out, the quiet girl just smiles and claims because it's fun.
Subverted in Mobile Suit Gundam 00. After defeating Ali Al-Saachez, destroying his Gundam Arche and cornering him in a hallway, Lockon Stratos gives the man who killed his family one last chance at redemption. True to form, Ali whips out a gun while Lockon's back is turned...and is shot dead before he can pull the trigger.
In One Piece, Kaya's family takes in an apparently down-and-out man and makes him their butler. He is secretly the pirate Captain Kuro, who develops a long-term plan; kill the entire family, steal their fortune, and retire on it.
Done likely by accident with Aokiji and Robin: Aokiji lets her live in spite of his order from the World Government, but, in spite of his warning to keep out of trouble, she's currently part of a crew whose leader declared war on the World Government.
Don Krieg and his crew were starving after their fleet was destroyed by Dracule Mihawk. Sanji fed them over everyone else's protests. Don Krieg "thanked" him by attacking him the moment he felt satiated and declared his intent to claim the floating restaurant as his new flagship. Sanji likely knew this would be the outcome. He just thinks starving to death is such a horrible way to die that he won't let anyone starve.
In the Fishman Island arc, Robin references this trope; when Jimbei asks her to free the slaves Hammond is using for his Slave Tank, Robin is disgusted by what Hammond is doing, but expresses concern that the freed slaves will attack both her allies and enemies, hating Fishman Island after what they've been through. Jimbei says that they can simply fight them off if this happens and that he can't stand Hody's men acting like the Celestial Dragons any longer, persuading Robin to free the slaves, who help the Straw Hats against the New Fishman Pirates.
In Okane Ga Nai, Ayase saves Kanou, only to end up 4 years later as Kanou's love slave.
Rurouni Kenshin: The starving, lonesome little kid Enishi almost dies in the streets of a foreign country (China) until a rich Japanese family saves him, even going as far letting him stay for however long he needs, no questions asked about his obviously painful circumstances. He slaughters them and takes all their money.
A comic serial on the Tales of King Arthur had the Frog and Scorpion tale being told during an Enemy Mine situation...up to the point where the frog swims across the river with the scorpion on its back. Later on, he privately reveals the Downer Ending to his friend and jokes dryly that the story is a lot better without it.
Shinzo: This happens quite a lot; when Yakumo shows kindness towards a villain, you can bet they'll try to kill her anyway. Even regular Enterrans will betray her kindness in a second; Yakumo saves an Enterran child, but once the villagers find out she's human, they try to burn her.
In Tsukigasa, a group of robbers save Kuroe's life and have him stay on as their doctor. Five years later he ends up stealing their special maps, running off, giving them to his former friend who is a samurai so they can be tracked down, and personally killing the two that hunt him down. All because they were going to rob his Love Interest.
Not quite a straight example: in Code Geass, Lelouch uses his Geass to steal a Knightmare Frame from a Britannian soldier named Villeta Nu. He leaves her alive, the Geass clouding her memory but still leaving vague echos that lead to Villeta causing the death of Lelouch's friend/possible love interest Shirley and screwing him over by revealing his identity twice.
Mobile Suit Gundam SEED Destiny: poor, poor Shinn. The only way to save Stella was to send her back to Neo, the only one who has the medical equipment to save her. He promised to keep her far from battlefields. What happens next? Neo puts her into the cockpit of the Destroy. Then Kira has to kill her to stop the destruction of Berlin.
Yzak and Deerka are a curious example. Chairman Durandal saved them during their trial for war crimes. But in the last episodes, they side with Lacus. So, here we have a Villain with Good Publicity saving some anti-heroes, and they bite him back by siding with the true good guys.
The myth of the frog and scorpion is heavily discussed during the second half of Edens Bowy. The plot involves The Hero and The Rival being two of the only God Hunters in existence, two Floating Continent warring heavily to get their hands on the Hero, protected by an Angelic Macguffin Girl who is responsible for said Hero's realization of his true nature. Much agonizing and angsting were had to contemplate inevitability of one's role; namely, must the hero surrender to his nature to kill his Love Interest when she's an Angel, even though she's responsible for his survival so far? The resolution to this is...complicated.
Interestingly, during the Where Are They Now epilogue, said rival now earns his keep by telling the tale of the scorpion and the frog, with his own twist at the end.
Subverted in an episode of Samurai Pizza Cats. Bad Bird is about to fall off a cliff, and Speedy grabs him by the arm just before he falls. Bad Bird asks why he's helping him, since he's an enemy. Speedy realizes he's right, and lets him fall. This is especially interesting because Bad Bird ends up being redeemed at the end of the series.
Sets up the plot in Jojos Bizarre Adventure, with George Joestar and his son Jonathan as the Farmers and Dio Brando as the Viper. George and Jonathan's kindness costs them their lives, leads to countless other deaths, and nearly causes the end of the universe.
In Pokémon, when the Team Rocket trio got stuck in a cave with Brock and a scientist, they agreed to help each other to get out. When they found an opening they immediately went back into stealing Pikachu.
Occurs in a horrifying manner in the 52 miniseries set in the year after Infinite Crisis. Osiris, the brother-in-law of Black Adam, the (sort of) Evil Counterpart of Captain Marvel, takes in a lonely anthropomorphic crocodile as a pet/family member whom he names Sobek. For most of the series, Sobek is depicted as a cowardly yet friendly fellow with a huge appetite. He is actually one of the Four Horsemen of Apokolips, Eldritch Abominations that hail from Apokolips and given bodies by the Mad Scientists that also star in 52. "Sobek" is actually Yurrd the Unknown, Lord of Hunger. Sobek is a Big Eater because his hunger can only be satisfied with the flesh of a Marvel. He manages to trick Osiris into depowering himself while Osiris is guilt-ridden after accidentally killing an attacker. Sobek eats Osiris alive; the depiction in the comics is rather horrific. When confronted with this by Isis, Osiris' sister and wife of Black Adam, what is the traitor's response?
In a Batman Detective comics storyline, the Joker gets hit by a truck after trying to kill Robin. He gets taken in by a magician who came to Gotham to study its "fascinating" criminal element. The Joker repays his kindness by teaching him some tricks of the trade. Then the Joker garrotes him and steals his identity to facilitate (oddly enough) a Batman Gambit to get Batman into one of his more clever deathtraps, not that it works. It's the Goddamned Batman. The Joker even refers to the "Farmer and the Viper" story while recapping his scheme to Batman.
This is the Superhero Origin of Freddy Freeman aka Captain Marvel Junior, before he became Captain Marvel after Crisis on Infinite Earths. Freddy and his grandfather were fishing in a lake when Captain Nazi is thrown into it by Captain Marvel in the middle of their battle. Freddy and his grandfather help rescue Captain Nazi, who repays them by killing the grandfather and crippling Freddy. Captain Marvel shares the power of Shazam with Freddy to save him, turning him into Captain Marvel Junior.
A variation on the tale itself comes in the Academy Comics' Robotech II: The Sentinels Halloween special, where after going with an Away team against the wishes of his wife Lisa, Rick Hunter explains his actions with the story, basically telling her that he's always gonna be a little headstrong and willing to take risks. To which Lisa says: "So the moral of the story is you're a lying snake, huh?"
Played back in forth in a comic for Transformers Animated where Ratchet is shown helping a Decepticon suffering from "Cosmic Rust", a disease some Decepticons released in the middle of a battle. Ratchet does it on the grounds that while the commanders knew the score for doing such a thing, it's no reason to abandon a soldier. Then is turns out the guy was the one that made the disease, and infects Ratchet with it after being cured. However in the process they made a cure for the disease that Ratchet was able to take back, and he'll probably be able to save plenty of Autobots if they can manage to replicate it.
Usagi Yojimbo also makes use of the "Farmer and the Viper" story when a hapless fisherman rescues Jei-sanafter the latter was stabbed in the stomach and tossed off a cliff into a raging river and fails to notice Jei's Milky White Eyes, ominous voice, and the mysterious chill that follows him. Jei even tells the story to the fisherman right before Jei kills him with his bare hands.
The idea of The Power of Love failing to redeem is featured in Johnny the Homicidal Maniac, when Devi asks Johnny on a date. All seems to be going well at first, until Johnny realises that he's found someone who actually makes him feel happy. He then tries to murder her, the one person who ever showed him any kindness in order to "immortalise the moment." This goes to show how completely fucked up his mind is, as well as kill the idea of any more romance in the series. Devi gets away though.
In The Sandman, Loki's urge to punish Morpheus because Morpheus helped him escape his eternal torment. Odin even cites this Aesop when pointing out to Morpheus how it is in Loki's nature to repay kindness with malice and ingratitude. Turns out to be an Invoked Trope on Morpheus's part; Loki's actions are all part of Morpheus's plan.
Loki does it again in Journey into Mystery, going so far to lampshade it. while he keeps reassuring Thor of his good intentions, reciting him the first verses of The Scorpion and the Frog, he still betrays him while telling "I'm no scorpion... for I am Loki!")
The Question recites a version of this parable to himself after he is attacked by a biker who he just saved from a fire.
Deadshot references the frog and scorpion version in Secret Six after apparently betraying the team.
In Sonic the Comic, Super Sonic was actually Sonic's Super-Powered Evil Side. During one story they got split apart, and Super Sonic lost both his power and his memory, becoming far more mellow, and befriending a magician called Ebony, who helped him get back on his feet. At the end of the series, Ebony and Super Sonic showed up at the final battle against Chaos, Super Sonic dying as a result of losing his power. Super Sonic absorbed the energy from Chaos, restoring his power... and his former Omnicidal Maniac personality. Fortunately, unlike most examples of this trope, he didn't kill Ebony. But she was forced to merge the two Sonics back together to stop Super's rampage.
An issue of The Batman & Robin Adventures featured this in an issue called "Dagger's Tale". The title character is relating to when he followed this to a young hotheaded inmate, revealing how when he attempted to break out of prison with an Ax-Crazy partner it went horribly wrong and said crazy partner decided their partnership wasn't working out. Batman saves Dagger at the last minute. He's astonished for a second ("You-You saved me?!" "I save everyone."), but after a remembering that Batman had previously gotten him captured in the first place decided to pay him back by attempting to stab him in the back, only to be punched out by the Dark Knight. After finishing things, he urges the inmate to not make a stupid mistake like he did and just serve his time out.
In Don Rosa's The Life And Times Of Scrooge Mcduck, Scrooge encounters an unnamed South Afrikaner ( who later turns out to be a younger Flintheart Glomgold) after the mining camp he had been a part of left him for dead for his numerous acts of thievery by tying him to a wildebeast. Scrooge saves his life and even shares his camp with him. The Afrikaner repays him by stealing all his supplies in the middle of the night and leaves him stranded in the wastelands. It's even lampshaded with Scrooge calling the Afrikaner a viper.
In Light and Dark The Adventures of Dark Yagami, after a nuclear bomb goes off, Kyosuke Higuchi "Yotsuba" is killed in a nuclear bomb blast and asks Dark to save him with his Life Note. Dark does and Yotsuba immediately tries to kill him for his master L.
In A Cure for Love, after having Watari killed Light feels a bit uncomfortable later when he remembers how Watari saved his life.
In the film Flesh and Bone, a starved and abused boy is discovered by a kind family. They take him into their home for the night to care for. When they go to sleep, the boy lets in his father (James Caan), who then proceeds to kill the whole family before robbing the house. This is a ploy the father and son had repeated many time before and since, till the boy was able to live on his own.
The British humor film Keeping Mum has what might be considered a (on the whole) well-meaning (though definitely not good) snake. Grace, the new housekeeper (who happens to be an elderly released murderess) becomes genuinely grateful that the family she has moved in with is happy and grateful she's come, particularly Walter (aka. Mr. Bean). Compounded with her being Gloria's mother, she decides to help the family and goes about being a decidedly murderous Mary Poppins to the Goodfellow family. First killing a dog that kept Gloria up, then the owner when he snooped, and finally Gloria's peeping tom paramour because he was causing Gloria to destabilize the family. All in all, she did the family a world of good, however she may well have unlocked her daughter's murderous side.
In Toy Story 3, Buzz and Woody risk their lives to save Lotso from the dump shredder, even though he had previously tried to kill them. Then, at the dump incinerator a few minutes later, it's Lotso's turn to repay the favor. Instead, he leaves Buzz, Woody, and all the toys to burn to death.
In the backstory of MirrorMask, the Queen of Light took in the Evil Princess, who repaid her kindness by stealing the charm that kept the Queen and the realm alive.
And let's not forget that after leaving the world of Mirrormask and trapping its creator inside, she was systematically destroying the paintings in the real world that were its anchor. All just to get away from smother dearest.
In the opening scene of Halloween 5: The Revenge of Michael Myers, Michael is nursed back to health by a hermit after falling down a mineshaft and nearly being shot by local authorities. Then, a year later, he wakes up from a coma and murders the hermit.
In the 2007 remake, when Michael escapes the institution, the only security guard who showed him compassion and kindness throughout his fifteen-year incarceration is given an extremely brutal and over the top murder: tossed around like a ragdoll, head dunked in sink four times, and finally head squashed by thrown TV. In contrast, the other guards, most of whom bullied and demeaned him, are typically stabbed or neck snapped.
In The Coen Brothers film Millers Crossing, Tom is supposed to take Bernie into the woods and kill him (Bernie grifted the wrong mobster), but when he is supposed to do so, Bernie's constant pleading and weeping convinces Tom to take pity on him, and he lets him go. Shortly thereafter, Bernie shows up at Tom's home and proceeds to blackmail him by threatening to walk around in public, even though that would probably get him killed by somebody with more the stomach for it than Tom. While pleading, Bernie even makes the argument that he shouldn't have to die for grifting, because "I see an angle, I take it," somewhat paraphrasing the Scorpion's excuse, "it's my nature." Bernie's waterworks didn't work the second time he was in the position to be killed by Tom.
In The Thief of Bagdad, Abu, while stranded on a deserted beach, discovers a bottle. Opening the bottle, he unleashes a huge genie, who because of his imprisonment grew to hate those who lived free and swore to kill his liberator. Abu tricked the genie into returning to his bottle and threatened to toss him into the sea. The genie was then able to regain his freedom by granting Abu three wishes.
The Devil's Carnival, which overtly bases chapters of the story on Aesop's Fables, uses the Scorpion and the Frog story in several ways. First, one of the female leads dies during a fight with her abusive boyfriend. Once in Hell, she comes across a hoodlum locked in jail, and kindly returns his knife so he can use it to pick the lock and get free. Once freed he convinces her to take part in his "knife throwing act", where he sings a song mocking her before throwing a dagger into her heart. Finally the story is summarized in a second, innuendo-heavy song about a trusting young frog falling for the "prick" of a scorpion's tail.
A Zig-Zagging Trope in the 2000 live-action adaptation of How the Grinch Stole Christmas!. Here, the Grinch is a green-furred baby who is persecuted throughout his childhood and finally driven out of Whoville and up to the isolation of Mount Crumpet, where he grows to maturity. Cindy Lou Who becomes convinced that the Grinch is not completely evil and urges the townspeople to include him in their Christmas festivities. But not only are the Whos unreceptive to this idea at first, but the Grinch himself has become so misanthropic that he does not want to be treated kindly anymore. Cindy at length gets both sides to change their minds, and the Grinch is made the guest of honor at the Whoville Christmas festival - a position he does not enjoy. Even so, the Whos shower him with kindness and the Grinch grudgingly plays along... until the time of the gift exchange comes and he is awarded a "gag gift" of a razor - an object carrying Unfortunate Implications for him because as a boy he had been mocked by the other children for his green whiskers, and when he tried to shave them off he succeeded only in cutting himself and getting mocked for that; this was the final injustice that drove the Grinch to flee from civilization. His temper boiling over, the Grinch lectures all the Whos about their hypocritical attitude toward Christmas before setting fire to the Christmas tree in the town square and fleeing the scene. But when he discovers that the Whos had a spare tree to continue the festivities, he becomes even more filled with hatred and finally embarks on his mission to steal all the townspeople's present.
In The Lone Ranger Tonto's backstory involves him finding and rescuing Cole and Cavendish from the desert. After being nursed back to health, they proceeded to slaughter his tribe for silver.
In the Corey Haim B-Movie Prayer for the Rollerboys, Corey plays a homeless teen taking care of his little brother. He runs into an old friend who now runs a powerful roller blade gang. During the film, Corey saves the life of the old friend's dragon which earns him entry into the gang. The dragon thanks him by spending the rest of the film trying to turn Corey's old friend against him. Even lampshaded during the film itself.
In X-Men: First Class, Charles Xavier believed that he could help the emotionally damaged Erik Lehnsherr find some measure of peace and happiness by offering the latter friendship and a home, but Erik repays Charles' kindness with betrayal, abandonment, and a permanent (if accidental) spinal cord injury.
In X-Men: Days of Future Past, '70s Magneto's sole contribution to the venture is to derail things the moment he sees a chance to advance his cause at the expense of everyone else. As the endings of First Class and X2 show, this is something of a habit for him.
At the beginning of The Stepfather III, a rejected medical doctor gives the titular character face change surgery, only for the Stepfather to kill him after the surgery was done and after he stayed rent free in the doctor's house until he was healed.
One version of the trope-naming story (Brer Possum and Brer Snake) ends with the line, "Well, you knowed I was a snake when you put me in your pocket!"
An interesting inversion takes place in The Executioner. One-Man Army Mack Bolan sets off on a Roaring Rampage of Revenge when his family dies in a murder/suicide indirectly caused by Mafia loan sharks. A faction of the New York Mafia Commission, pointing out that their own organisation was created when former enemies made peace, suggest offering Bolan a deal in which he would now work for them. A rival faction is opposed, with one mob boss who's missing several fingers mentioning a pet alligator he tried to raise as an allegory. Although an undercover Fed urges Bolan to take the deal he rejects it, saying he can't let the Mafia even think that they've won.
Orson Scott Card used something similar in his story The Princess and the Bear. Having attempted to redeem the Evil Prince, the princess gives up on him and lets the Bear kill him. If this sounds like a Family-Unfriendly Aesop, it ought to be mentioned that the prince and the princess follow the standard cycle of an abusive relationship.
If any lesson is to be taken from Otherland, it's this: never date anyone whose last name is Dread. And who likes to be addressed as "More Dread." And whose idea of romancing you is setting a priest on fire for your amusement ...
The villain Achilles from Bean's side of the Ender’s Game series has a pathological need to kill anyone who has ever seen him helpless — including but not limited to a girl who lifted him from low-ranking thug to leader of a prosperous gang, a nun who got him off the streets entirely and enrolled him in a good school, and a doctor who dared use anesthesia to help fix his bad leg.
Subverted in Les Misérables, as Jean Valjean is taken in by the priest when no one else will after being paroled following nineteen terrible years in prison. Valjean assaults the priest and steals his silver in the night, but while escaping, he is caught by the police as a suspicious character. The priest tells the police that he gave Valjean the silver, and lets him go. This second act of kindness actually changes Valjean's nature, as he strives to be good in return for this following act of compassion. It's shown that being put in prison had thoroughly corrupted him in the first place. His crime was stealing bread to feed his sister's children, for which he got five years, with the sentence extended for every time he escaped.
Redwall's Veil Sixclaw repaid the Abbeydwellers for saving him by attempting to poison one of them. Then again, they may have saved his life but even before he attempted to kill them they always treated him as if he was going to anyway. His foster-mother Bryony, the only one who trusted him, considered this as a Freudian Excuse, but it didn't help.
Worse yet, even at the end of the book and his life, he himself feels like he is evil or just born bad, even though he saved Bryony, sacrificing himself to do that. It's also notable for being one of the few books where Redwallians are portrayed in a less-than-sterling light. They're good in themselves here, but their actions toward Veil are ambiguous at best, just as he is ambiguously good or evil. Bryony also seems very uncertain about him even afterward, and both seem to think she should have let him go long before.
This trope also applies to Chickenhound of Redwall, who is kindly taken in by the Abbeydwellers after they find him lying muddy, bloody, and unconscious in the middle of the road. He repays the gesture by stealing a bunch of random trinkets and killing Methuselah, although in his defense the latter was mostly an accident. About the only thing he does do that's him being nice to the Redwallers is tell them about Cluny's plans to tunnel into the Abbey, which turns out to be incredibly useful, but wasn't entirely altruistic on his part.
Pretty much any vermin Redwallers ever take in or help fit this trope. Salamandastron has Dingeye and Thura, who eventually kill Brother Hal and then flee the Abbey, stealing Martin the Warrior's sword and infecting the place with Dry Ditch Fever in the process. Hal's death was accidental and the Dry Ditch Fever was inadvertent, but the sword stealing was their decision, albeit while in a state of panic. The Bellmaker has the Redwallers take in two wandering corsairs, a captain and his Minion with an F in Evil. The captain ends up killing Mother Mellus and stealing a trophy cup, but the trope is inverted when the minion ends up killing ''him'' and returning the cup to the Redwallers, whereupon he becomes a good friend of theirs and is allowed back to the Abbey for visits.
In The Riftwar Cycle, Tal asks Nakor how he can swear an oath to serve the evil Duke Kaspar, who wiped out his people, as part of a ploy by the good guys to spy on him. Nakor tells him the "scorpion and the frog" version of the story and explains that he won't have to break his oath to Kaspar, because it's in Kaspar's nature to betray him first, which would render Tal's oath void. Sure enough, Kaspar turns on Tal and sends him to rot in The Alcatraz, leaving him free to enact his revenge.
Aristophanes quotes Aeschylus in The Frogs as saying: "Best not to rear a lion's cub in the City, but if you do, its ways must then be served."
In The Eye In The Door, the "viper" character tells this fable to the "farmer" character in order to explain his actions.
In Wuthering Heights Nelly Dean comes close to invoking this when she says that Heathcliff was "harbored by a good man to his bane," implying that Mr. Earnshaw inadvertently ruined his family by taking pity on a homeless orphan.
Invoked and eventually subverted in BattleTech's Blood of Kerensky novels. Anastasius Focht, the commander of Com Star's military mentions a variation of the fable to the Primus, suspecting her of trying to politicize his upcoming battle with the Clans and attempting to warn her that her penchant for doubledealing could defeat the treaty he was negotiating with them. She promptly plans to betray the Clans and the Inner Sphere at the same time, even calling the operation Scorpion, but the plan fails due to a Mole in the First Circuit, and is assassinated for her betrayal.
Referenced in ''Mara, Daughter of the Nile". "I plucked a lily from the gutter and it has turned into a viper in my hands." From Sheftu's perspective, he aided a fugitive slave girl and gave her a purpose and a future (and also fell in love with her)—only for her to turn around and betray him to the Queen. (Mara's side of the story is a little different).
The Doctor Who book Autumn Mist, set during the Second World War, has one at the end. Garcia, a young medic who has assisted the Doctor throughout the adventure, decides to treat injured soldiers on both sides because he just wants to save lives. The first German he treats uses his dying strength to stab him with his bayonet, killing him.
In the second book in The Wolf Chronicles, Kaala has a chance to kill DavRian, the human who's been nothing but trouble and a danger to the wolves for the whole book: he'd fallen down a hill and gotten pinned by debris on the edge of a cliff, and all Kaala would need to do is push him and Make It Look Like an Accident. When the opportunity is offered, she refuses because it would go against the Promise and it's just wrong. He repays her by killing TaLi's grandmother and framing the wolves for it.
In The Vampire Chronicles, Claudia hunts by posing as a lost waif, then draining any good Samaritan who tries to help her. Lestat also plays the viper in The Tale of the Body Thief when, while trapped in the body of an impoverished human, he rapes a waitress who feeds him.
In the two-part Star Trek: Voyager episode "Scorpion", Captain Janeway plans a temporary alliance with the Borg in order to combat Species 8472. When she asks for Chakotay's personal opinion, he relates the parable of "The Scorpion and The Frog" mentioned in the page quotes, though with a fox in place of the frog. Oddly, the story as told is more tragic than the normal telling, with the scorpion apologizing for being unable to help its nature, when the Borg would have no such compunctions.
In the earlier series Star Trek: The Next Generation, Q actually uses this against the crew when he's turned mortal by the continuum, choosing a human form and going to them for help, assuming that their values and willingness to forgive "almost any offense" will mean they are willing to protect him from the variety of less-moral creatures he has tormented in the past, and who are willing to take advantage of his newfound humanity. He's not entirely right in this assumption, but right enough for subverting this trope in "Viper part" too, when Data's sacrifice moved Q into an attempt to save the ship at the cost of his own life.
Two episodes of Highlander: The Series featured an 800-year-old immortal named Kenneth, who is trapped in the body of a 10-year-old boy (Immortals stop aging whenever they are "killed" for the first time). Kenneth's standard procedure is to pretend to be a helpless immortal child who only recently found out he was immortal, and when he's taken in he waits for an opportune time and kills his protector from behind, stealing their power.
In an episode of MacGyver, the female antagonist is hanging from a ledge. MacGyver is all Take My Hand, but the woman stabs him, causing him to drop her to her death. Pete tells MacGyver the tale of "The Scorpion and The Frog" to calm him when he questions why she would do that.
Invoked in the Chinese TV adaptation of The Prince of Tennis, where Hai Tang (whose nickname on the court is "Viper") recounts this story as the reason why his teammates shouldn't get too friendly with Long Ma.
In Being Human, after the resurrected, amnesiac villain Herrick gets his memories back, he considers killing Nina as revenge on George for killing him, then he changes his mind as she was the only one of the main characters who showed him any kindness while he was in their care. Just when it looks like this trope is going to be subverted however, he decides "But then everyone would think I was going soft" and stabs her. She's pregnant, by the way.
The Bill. An elderly bank robber is caught in the act, and when asked why he'd risk the long prison sentence at his age relates the story. The episode ends with him saying "I'm a scorpion." (i.e. It's my nature).
In the first episode of Supernatural, a ghost is killing men who see her hitchhiking and pick her up. The trope is arguably averted because her victims have an ulterior motive—she is smoking hot and the drivers are hoping the pickup turns into a hookup and she seeks them to out to punish them for trying to cheat on their significant others.
Later in the season, Meg, a frequent hitchhiker who it turns out is a victim of Demonic Possession, is shown killing men who pick her up and using their blood to communicate with other demons.
In the backstory of Power Rangers Time Force, Big Bad Ransik was rescued and given life-saving medical attention by Dr. Ferricks. He responds to this kindness by setting the doctor's lab on fire and leaving him to die. This makes things rather awkward for the series' later attempts to sell him as a Magneto-esque Anti-Villain
An episode of Scrubs has J.D. pull a splinter from the Janitor's toe, and even bring up the parallel to Androcles' Lion (with the Janitor saying the story ends with the lion killing and eating the mouse anyway). The Janitor makes a show of offering unwanted payback, and finishes off by pointing out that J.D. could have just asked for him to stop messing with him (and steals his stethoscope when he tries to).
On LazyTown, oftentimes when Sportacus rescues Robbie Rotten, Robbie's next act is to try to do something else to screw over Sportacus.
The scorpion variant was referenced by Kevin when dealing with a lawyer who was being particularly feisty on Shark Tank.
Played with Xaro Xhoan Daxos. Daxos was taken in by the city state of Qarth (which is usually closed to outsiders), and proceeds to work his way up to a position of leadership- at which point he has the other leaders killed and declares himself king. However, Daxos attributes his treachery to his love of Qarth- he agrees with the slain leaders that it is a great city, but feels that it will grow stagnant if allowed to continue to be isolated from the rest of the world under their leadership.
The Daleks in Doctor Who. If someone holds a Dalek's life in their hands, the Dalek will always beg for mercy. As soon as you give them the chance though, they'll exterminate you without a second thought.
In episode of The George Lopez Show, George finds himself desperately wanting praise from his particularly ungrateful mother, Benny. When his wife Angie suggests renovating her run-down bathroom might get him that elusive "thank you," he throws himself into it full-force, fixing up her bathroom until it's showroom-new. Benny walks into the room, looks around, and... tells George the hook on the back of the door for her robe is too high. Later, when Angie is telling George not to be mad at her, he says he's not, saying you can't be mad at the scorpion for stinging you, it's in their nature. Instead, he's mad at Angie, who told him to pick up the scorpion in the first place.
Discussed in the Masters Of Horror episode "Pick Me Up". Near the end Wheeler relays Stacia and Walker the story in the form of a snake and a blonde woman. Walker already knows the punchline because he's heard the "scorpion and the frog" version. The point Wheeler makes is that he knows full well that he picked up another serial killer and expects him to show his true nature. The subversion is only that he's also a serial killer, so it'd be a scorpion helping another scorpion.
In one episode of Gilligan's Island, a hardened criminal came to the island, and proceeded to kidnap Mrs. Howell, then Ginger, and then Mary Ann, demanding a ransom for their return each time. (This was one of the few times that chest full of cash Mr. Howell had brought proved useful.) When Mary Ann was released, she told the others that he told her he planned to do the same to the other four, and then start over again, so the Professor set a trap for the criminal, and it worked. As the castaways held the criminal in a makeshift cell while the Professor worked on his ship, Ginger felt sorry for him, and asked if she could speak to him, remembering how she once acted in a movie about how a psychiatrist helped a criminal reform. Eventually, the others consented (except the Professor, who had his doubts) and Ginger's amateur therapy seemed to work; for a while, he seemed remorseful and willing to help. Unfortunately, it was an act; at the party they had before they planned to leave, the guy proceeded to steal their jewelry, and then escape on his own. That's when Ginger realized that that's how the movie ended.
In one episode of 24, a neighbor helps a character played by Kal Penn from being attacked by people who target him for his race, unfairly assuming he's a terrorist. Later, it turns out that he actually is, and he kidnaps the neighbor and his family.
Given a Perspective Flip in Nick Cave's song "Fable of the Brown Ape", where the snake is portrayed as a victim rather than a threat.
Al Wilson's "The Snake" is a variation of the trope-naming story set to music. A tender-hearted woman finds a half-frozen snake, and takes it home with her and warms it up, but is bitten in much the manner of the farmer.
"I saved you," cried the woman, "and you bit me, but why? You know your bite is poisonous and now I'm gonna die." "Oh, shut up, silly woman," said the reptile with a grin, "You knew damn well I was a snake before you took me in."
Megadeth's song "The Scorpion" alludes to "The Frog and the Scorpion" in the refrain. The lyrics are otherwise more about a figurative scorpion rather than a literal one.
The song "The Snake" by Mediaeval Baebes is sung in Old Spanish and matches this trope almost completely with the difference being that the snake starts growing dangerously big and when the farmer tries to kick it out of his house, it squeezes him to death instead of stinging him. The lyrics apparently come from a fable from El Libro de Buen Amor (The Good Book of Love) by Juan Ruiz, Archpriest of Hita from the 14th century AD/CE.
A variation involves the Lion and the Unicorn. The two were enemies, but the Unicorn agreed to let the Lion borrow its horn. The Lion then ambushed the Unicorn and stabbed it with the horn. When the Unicorn asked why the Lion did this, the Lion responded by asking why the Unicorn trusted its worst enemy in the first place.
The Lion and the Unicorn are respectively the heraldic supporters for England and Scotland, by the by. It's probably best not to elaborate on this point.
Happens again and again whenever the heel is a Dirty Coward. You can bet farthings to fritters that as soon as the face has overpowered the heel, he'll be on his knees crying: "Nooo! Noooooo!" Any face who is not Genre Savvy enough to just hit the guy anyway after that will be deservedly punished with a thumb to the eye or an even more painful indignity. (If Ric Flair is the heel, the odds of this not happening are pretty much nil.)
Jake The Snake once referenced the aesop in a story as well, demonstrating that the concept has been in the ring for decades. However, in his version, the man asked the snake why he betrayed him as he lay dying, and the snake spoke "Oh, come on. You knew I was a snake the day you found me."
In Ring of Honor, CM Punk started as a heel, turned face, and was receiving massive cheers by the time he won the ROH World Heavyweight Champion, at which point he made a promo referencing Aesop's story and declared "I'm still a snake, you idiots!", declaring that he was going to take the title belt with him to WWE, and signing his WWE contract on the ROH title belt. Of course, as an indie darling and a good performer, he was Face for over a year (and not just with the smarks) since hitting WWE...and then he assaulted fan favorite Jeff Hardy and stole his title after Jeff had been champion for about five minutes.
As part of a Continuity Nod, he did basically the same thing in WWE. This time, with a very interesting result.
Edge did something similar in 2010. Returning from injury during the Royal Rumble, he came back to a huge ovation as he won the match and went into Wrestlemania as the challenger for the Wolrd Heavyweight champion. After coming up short too many times and then getting traded to Raw, Edge revealed his true nature in rant, going on about how switching shows ruined his opportunity to be the top face of Smackdown.
A rare example of a Heel doing this to another Heel:
During the build to ECW Barely Legal, April 13, 1997, a masked man who was pretty much believed to beRick Rude was threatening "The Franchise" Shane Douglas and promised to unmask if Douglas successfully defended his ECW World Television Championship against Pitbull #2 (w/Pitbull #1) at the PPV. Douglas won his match, and what was believed to be Rude's voice came over the sound system, saying that he'd take his mask off, but Douglas has to "give up the girl" (Francine) or he'd give Douglas "the ass-kicking of a lifetime." The masked man then walked out in Rude's trademark robe. Shane pushed Francine toward him. The masked man kissed Francine, who, believing it was Rude, appeared to pass out in delight. Then, one of Douglas' riot guards took off his helmet, revealing himself to be Rick Rude. The masked man unmasked and took off his robe, revealing, instead, Douglas' Triple Threat ally "Bulldozer" Brian Lee, who then chokeslammed Douglas. Douglas, Chris Candido and a clearly disgusted Francine ran off, vowing revenge.
After a few more months of making trouble for Douglas for his own amusement (including pulling up Francine's dress to reveal her panties during Douglas' match with Chris Chetti at Buffalo Invasion on May 17th), he surprisingly turned on Tommy Dreamer and the Sandman in a six-man-tag against Rob Van Dam, Sabu and Jerry Lawler at Heatwave on July 19th, giving the Triple Threat handsign. Douglas defeated ECW World Heavyweight ChampionSabu and Terry Funk in a three-way-dance to win the title at ECW's second PPV, Hardcore Heaven, on August 17th. This led to Rude becoming a manager for the Triple Threat (now, Douglas, Candido and Bam Bam Bigelow, w/Francine) and handpicking opponents for him, as thanks for Douglas giving Rude one night with Francine. Douglas defeated Al Snow, Balls Mahoney and Phil LaFon. Then came the October 16th show at the Elk's Lodge in Queens, NY. Rude told Douglas that he had found him an opponent who "ran roughshod over the WWF." Douglas asked, "You got me the Boy Toy?"note This was during the time when, due to the interpromotional relationship between ECW and WWE, Rude was going back and forth working with both Douglas and his hated enemy Shawn Michaels, stemming from Douglas' run-ins with the Clique in WWE in 1995 as Dean Douglas. Then, "Welcome to the Jungle" started playing, with Douglas doing a great Eye Take, as BAM BAM BIGELOW was revealed to be Douglas' opponent, meaning that Rude had tricked Douglas TWICE in SIX MONTHS.
In the game Legend of the Five Rings, the classic story of the frog and the scorpion is told, but when the frog asks the scorpion why he doomed them both:
Why do the Scorpions wear masks? Because their founder wore a mask after hearing this. He didn't want anyone to see he COULD NOT STOP SMILING.
Specifically, Bayushi smiled after he heard the story, telling Shinsei that he understood the meaning of the story. His eyes revealed that he didn't really have enlightenment. So Shinsei hit him in the mouth. Bayushi then covered his mouth, because it was what had lied. The Scorpion clan wear masks in memory of the event, and to make it easier to lie. It's hard to believe that a spymaster and the man that taught an Empire to deceive somehow couldn't stop smiling.
A variation: Knights of the Old Republic, Jolee Bindo, having lived as a hermit on Kashyyyk for twenty years, helps the player character out and then follows you offworld. For a good while he claims that his reasoning is that he'd finally gotten sick of the planet, he wanted to see the stars again. But as he gets to know you he tells you a parable about a young man who one day finds a snake in his village. He follows the snake, helping it away from the village and into a great desert. Without food or water to be seen, the snake bites the young man. The snake then asked why the man followed him, and the man replies; "Did I follow you? I thought I was leading you away from everyone else!" Considering that the player character is Darth Revan, that parable might or might not apply to you. At any rate, this particular snake can choose whether or not to bite.
General Azimuth's trust in a young Cragmite is the reason Ratchet is the last Lombax in the universe.
In Age of Wonders the Keepers attempt to raise some goblins to be good. The Cult of Storms has no trouble convincing the goblins to riot and help kill the Keepers' leader.
In Dragon Age: Origins, Sten was left for dead when the darkspawn massacred his squad. When he came to, he found that he had lost his sword (without which he could never go home again) and slaughtered the villagers who picked him up and nursed him back to health in blind rage. He follows the player as his own Redemption Quest because of this.
In Fallout: New Vegas, the Courier can horribly screw over both of the people involved in saving their life after they were shot in the head and left for dead, first by joining up with the Powder Gangers to destroy Doc Mitchell's hometown of Goodsprings, then by blowing up an army of Victor's securitron "brothers" and murdering his creator, Mr. House.
In Batman: Arkham City, Batman saves a Two Face thug from being lowered into a vat of molten steel by Joker Thugs. No sooner does Batman take his eyes off the thug does he try to knock you out.
Heavy Rain. Without spoiling anything, suffice it to say that during the ending showdown with the Origami Killer, it is entirely possible that the fight will end up on a tall structure, and properly dodged or countered attack will leave the killer hanging by his fingertips over a deadly drop. The killer will humbly ask for your aid, and you have the option of pulling him to safety or letting him fall. Should you choose the former, the killer will give you a sincere-sounding word of thanks before immediately resuming his attempts to kill you. Even the most Genre Blind player would see this outcome a mile away, but the killer is so Faux Affably Evil that most players are tempted to at least take a chance on saving him.
If you killed the Rachni Queen in the first Mass Effect, the Reapers create a husk Queen in the third game to produce Ravagers. The Queen is understandably enraged at having been created as a monster to create more monsters, and wants to help fight the Reapers... supposedly. She ends up betraying you, not only taking away the Assets she provided but also decimating your Engineering Corps. If you saved the queen...this trope is averted.
In the Tekken series, zombie cyborg former Interpol agent Bryan Fury is saved by Dr. Boskonovich and installed with a perpetual generator. Bryan's thanks is to trash the lab and kill members of the Manji clan, who were led by Dr. B's close friend Yoshimitsu.
Likely in any game with multiple factions but a Gang Up on the Human mentality. If you run into a battle to save one group it's far more likely that everyone will immediately start ignoring eachother and focus entirely on destroying you.
This is Kira's ending in Mortal Kombat Armageddon. She uses the life energy granted to her by the Elder Gods to bring back Kobra, her old Black Dragon team mate who died in battle, and who was a pretty big Jerk Ass when he was alive. Kobra repays the favour by killing her, calling her weak and saying that she should have left him dead. The other way around is the same too, in Kobra's ending, he also had the Elder Gods revive Kira, who proceeds to kill him with a kiss of death.
A good chunk of Tales of Xilliarelies on this trope, so much so that it's barely even a spoiler. Jude forgives Alvin for betraying the party about four or five times, despite the fact that one of these times almost directly causes Milla's death. And of course, he just keeps on betraying you, and every time it gets worse. He's not really evil, though - he's just in possession of a Dark and Troubled Past.
In Skyrim Sometimes when fighting Bandits they'll crouch down and proclaim they yield and beg for their lives. So okay, you spare them... two seconds later they get a second wind and try to kill you again. And no they are not ever scripted to "Yield for good"
In Touhou there was a man named Iwakasa that saved a young girl while he was on a misson to destroy a dangerous artefact. The girl tagged along him on his misson but after some events on Mount Fuji he was killed by the girl on the decent and she took the artefact for herself. The artefact was the Hourai Elixir and the girl was Fujiwara no Mokou.
In Drowtales, Ven'nedia accepts the highlydemon taintedCreepy Child Kharla'ggen into their "clan" (at that point more a group of tainted drow seeking mutual protection and understanding) to try and help her adapt to her condition and live a normal life. She and her daughter treat her like family, and even normalize her enough that, while still incurable, she settles down. Then their clan is attacked and nearly destroyed, and she kills all the invaders singlehandedly. When rival Sene'kha proposes using Kharla'ggen as a figurehead leader she is opposed, and when voted down tries to run away with her daughter Kiel'ndia ... only to have Kharla'ggen turn her into a living puppet, put on display over their main entrance to scare enemies (and allies).
The Scorpion and the Frog parable, above, inspired Vriska Serket in Homestuck (or rather, she inspired it), as her motif is arachnids and has a self-destructively malicious nature. Appropriately enough, she dies (again) by trusting her worst enemy, Terezi, not to kill her when her back is turned. Terezi, having foreseen the consequences, stabs her in the back.
Subverted in Bob and George, in the Mega Man 3 storyline, everyone is telling Dr. Light he's an idiot for trusting Dr. Wily. As expected, Dr. Wily betrays them and steals Gamma and the power crystals, only for Gamma to fail as Dr. Light had the power crystals replaced with faulty ones, and Dr. Light saying he wasn't stupid and took precautions.
Dr. Light: Just because I gave Dr. Wily the benefit of the doubt doesn't mean I didn't have a back-up plan.
One day the Baron was out a-walking, when by the side of the road, he found two injured constructs. They possessed the faces and torsos of beautiful women, and the bodies of deadly serpents. "Help us, kind sir," the creatures begged. "Of course," said the Baron. He took them to his castle, and patiently nursed them back to health. And when they were both once again sleek and strong, the first one bit him with her deadly, poisonous fangs. "Why did you do that?" screamed the second construct. "He helped us!" The first construct shrugged. "He shouldn't be surprised. He knew we were monsters when he took us in." "But we don't have to act like monsters," said the second. "I have chosen not to!" "And that," said the Baron to the second construct as he revealed the armor beneath his clothing and drew forth his terrible sword, "Is why you will live."
Avatar: The Last Airbender. While Aang, SifuThou Shalt Not Kill, consistently saves Zuko, Sokka, who's spent his whole life in a war, asks why they should help him in the first season finale, given that all the previous times they've saved him or shown mercy he's tried to capture Aang. This is brought to a head when Katara bonds with him over their (supposedly) dead mothers and offers to try healing his scar... only to face him battling alongside his Magnificent Bastardsister in a battle that temporarily cost Aang his life.
In the third season Aang was ultimately proven right, though - he needed a firebending teacher at the exact same time Zuko did his Heel-Face Turn.
In a less extreme example, during Zuko's exile in the Earth Kingdom, a woman and her mother take him and Iroh in for dinner. As they leave, Zuko steals their Ostrich Horse.
Also, in "Imprisoned", Haru uses his Earthbending to save an old man from a cave-in. Later that night, the old man rats him out to the Fire Nation and gets him arrested.
Batman: The Animated Series: Killer Croc escapes while escorted by train to a prison, Batman in hot pursuit. They fall off a cliff and are knocked out. Croc wakes up in a secluded home owned by former circus performers. It's Croc's perfect chance to start a new life. Naturally Croc claims Batman is evil to get their help in capturing him. Then Croc captures everyone and plans to kill them and run off with their retirement money. When he's eventually foiled, he does seem a little regretful as he's taken away.
Lisa makes it her goal to help Burns rebuild his lost fortune in a socially responsible way. He takes to her teachings with zeal, but in his efforts to follow her instructions he creates a recycling plant that strip mines ocean life into an all purpose slurry. It ends with the memorable scene of Lisa running house to house begging people not to recycle!
It then happens again, many seasons down the road, when Burns is brain-damaged and has lost his memory. Most of the Springfieldians take advantage of this to get revenge on him for everything he did to them. Lisa takes pity on him, and ends up restoring him to his former, evil self, with the added lesson that hatred is the only thing keeping him alive.
An earlier episode had Marge take an interest in reforming Jack Crowley, a prisoner convicted of armed robbery (voiced by Michael Keaton) by encouraging his casual interest in art. The warden agrees to let Marge take Jack into her home and help him find a job as a mural painter. When Marge hears that Principal Skinner wants a mural painted for Springfield Elementary, she suggests Jack for the task. But Skinner forces him to paint a treacly, cutesy scene instead of what he actually wanted to paint - and then, to add insult to injury, Skinner has Jack take all the blame when the mural proves unpopular. Jack has to be restrained from physically assaulting the principal, and soon afterward a plot to burn down the school is uncovered. Marge finds Jack hiding in the playground and accuses him of going back to a life of crime; Jack lies that he's innocent, prompting Marge to believe him and to help him escape. Marge's reward for this is seeing Jack pour gasoline on Skinner's car and light that on fire in full view of everyone, laughing diabolically. Jack is quickly arrested and finally confesses to indeed starting the school fire, but not the car fire, leaving Marge disgusted.
The episode "Action Figures" of Superman: The Animated Series featured a couple of kids sheltering an amnesiac Metallo, who they think is a good robot who can be like Superman. In the beginning, he does do good and helps save the kids and trucker, but as more of his memories return he reverts to his evil persona. In "gratitude" for helping him, he tries to kidnap the kids and leave the volcanic island their parents are researching. When one of the children tries to appeal to goodness, he replies "Steel Man? Steel Man is dead! And so are you Superman!" Lois Lane later consoles the children with "He was good, when he was with you. Now all the goodness in him is buried, along with the rest of him".
An episode of Mickey Mouse Works involved Mickey rescuing Pete from the cold and warming him up inside the mouse's cabin. Being the greedy prick he is, Pete reveals he only pretended to be freezing to death as he and his cousin take over Mickey's cabin. Of course, being a cartoon about Disney's beloved mascot, Mickey not only managed to turn the two against each other, but, in the end, tricked the criminal dimwits into turning themselves into the police.
On Jimmy Two-Shoes, Jimmy agrees to care for a weavil he believes to have injured, despite Beezy's warnings that weavils are Always Chaotic Evil. Indeed, the weavils take full advantage of him, slowly transforming him into one of them.
In the oft-disputed third season of Gargoyles, a common tactic the villains used was having someone pretend to be in danger in order to lure the heroes into a trap.
In an episode of Family Guy, Lois finds out she has a brother (voiced by Robert Downey, Jr.) who was put in a sanitarium by her parents after a traumatic event and kept a family secret. Lois, assuming her awful parents were just being awful again, brings her brother home to live with her. It turns out he's a dangerous psychotic who kills fat people. He goes on a killing spree that ends with him trying to kill Peter.
This was also the point of the episode where Peter befriends OJ Simpson. The Griffins come to the conclusion the OJ is really an O.K. guy who deserves the benefit of the doubt, only for him to stab a woman in plain view of everyone and go running off on a mad killing spree.
In the My Little Pony: Friendship Is Magic episode "Griffon the Brush Off," Pinkie Pie declares that she'll have to do something about Rainbow Dash's Poisonous Friend Gilda. We're led to believe this involves provoking Gilda with party pranks until she loses her temper and Rainbow can see how bad she is, but it turns out Rainbow herself set up the pranks and it was only chance that Gilda ran into all of them; Pinkie's plan was simply to throw a party for her in the hopes that it would get her to lighten up. Needless to say, it fails miserably, but at least Rainbow does learn Gilda's true nature and kicks her to the curb.
The Smurfs episode "All Creatures Great And Smurf" has the adult Nat Smurf getting his fellow Smurfs to help get Azrael's paw out of a bear trap by bringing him into the village. At first Azrael seems grateful, but upon hearing his master Gargamel calling out for him, he reverts back to his own evil nature and is almost ready to tear Nat Smurf to shreds when he gets chased off into the forest by a larger creature. Nat Smurf mistakes this situation for an Androcles' Lion.
A skit on Robot Chicken referenced the famous Scorpion and the Frog story. The skit pretty much lampshades how insanely nonsensical and Stupid Evil someone would have to be to act like the scorpion. This time, the Frog catches the scorpion just before it stings him and is nothappy with him.
In one episode of Evil Con Carne, the title character and Cod Commando are marooned together on an island, and Hector successfully uses this trick on Cod three times in the same episode. (The fourth time he tries it, when success is vital to escaping, Cod wises up, and leaves him behind.)
Early on in X-Men, when Sabretooth winds on at the X-Mansion's doorstep, Professor Xavier takes him in and attempts to help him overcome his bestial urges, with Wolverine being the only objector. It goes about as well as you can expect: when Jubilee attempts to help him out with his hospital restraints so they won't be too uncomfortable, Sabretooth breaks loose and attacks her, forcing Wolvie to fight him off, which also results in him getting injured in the process.
Adventure Time has the Magic Man, who teaches us all an important lesson about not giving sugar to jerks.
Kung Fu Panda Legends Of Awesomeness averts this to some extent in the 'Po Picks A Pocket' episode, wherein Po is initially tricked into being kidnapped by a group of adorable, seemingly-innocent child thieves, even as young as toddlers. During Po's imprisoning, the kids attempt to justify this by explaining that they have no other option besides this, due to being held captive by their thieving leader. Po offers to break them out of their situation, and leads them back to the Jade Palace, where they appear to be settling in just fine...that is until they trick Po again, by imprisoning him in the Palace's dungeon so that the leader thief can steal a precious ruby. It isn't until Po points out they cannot split a single ruby between each other for profit, that the kids turn on their leader once again, now having completed the aversion of the trope.
Parodied in Richard Bartle's children's book parody, the SO Book of Spoons, in the story about The Farmer And The Fox.
This is the reason people are told never to pick up hitchhikers.
Serial Killer Charles Panzram was sent to Leavenworth for his crimes, on a 25-year sentence. At his sentencing, he'd told the judge that he would kill the first person to anger him, and did just that, killing the prison's laundry foreman. His sentence was upgraded to death, but a human-rights group tried to put in an appeal. Their reward was an angry letter from Panzram threatening to kill them all if they kept seeking an appeal. Understandably, they stopped.
Snopes shows that it can be as simple as con men, who try to get some act of kindness or cooperation, only to dump their expenses on the mark.